Universal Joint Yoke Ear Locking Against Cap Spin and Spreading
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Solution Overview
Problem
Existing universal joints in vehicle drivetrains are prone to bearing cap spinning relative to yoke ears and trunnions under torsional loads, leading to weakening and potential failure, with no effective structure to prevent the inadvertent spreading of yoke ears.
Innovation Solution
A universal joint design featuring a central body with non-rotatable trunnions and a locking assembly that inhibits movement of trunnions and yoke ears, ensuring secure attachment and preventing spinning and spreading under increasing loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional universal joints use bearing caps secured by snap rings, then the structure is simple and easy to manufacture, but the bearing caps spin relative to trunnions under torsional loads leading to weakening and potential failure
Solution Approach 1:
The patent employs asymmetric keyway features where the trunnion has a non-circular cross-section (e.g., square or rectangular) that fits into a corresponding keyway in the yoke ear. This asymmetric geometry prevents rotational movement of the trunnion relative to the yoke, eliminating bearing cap spinning while maintaining structural integrity under torsional loads.
Solution Approach 2:
The patent incorporates preliminary locking features during assembly, where the keyway and trunnion geometry are designed to automatically prevent rotation as soon as the trunnion is inserted into the yoke ear. This preliminary anti-rotation mechanism is built into the basic structure, eliminating the need for additional retention components.
2Strength
If existing universal joints lack additional locking structures, then the device complexity is low, but the yoke ears spread apart under extreme torque leading to weakening and failure
Solution Approach 1:
The asymmetric keyway-trunnion interface not only prevents rotation but also provides lateral support against spreading forces. The geometric constraint created by the non-circular trunnion fitting into the keyway resists the outward forces applied to yoke ears during extreme torque conditions, preventing separation.
Solution Approach 2:
The patent combines multiple functions into the keyway-trunnion interface: it simultaneously prevents rotation (anti-spinning) and resists spreading forces (anti-separation). This merged structural feature addresses both failure modes without requiring separate locking mechanisms for each function.
3Adaptability or versatility
If bearing caps are allowed to spin on trunnions, then the universal joint can accommodate misalignment and movement, but the spinning leads to loosening of snap rings and eventual ejection of bearing caps
Solution Approach 1:
The non-circular trunnion and keyway configuration eliminates relative rotation between components while still allowing the universal joint to accommodate angular misalignment between shafts. The asymmetric geometry provides a unique orientation that prevents spinning but permits the necessary pivotal movements for universal joint operation.
Data Source
AI summary
A universal joint for vehicle drivetrains and the like that eliminates the spinning of bearing caps relative to yoke years and trunnions and inhibits inadvertent spreading of opposing ears of a yoke away from each other under increasing torsional loads to reduce wear and failure of the joint. Broadly, the disclosed universal joint includes a central body having a plurality of pairs of opposite apertures, first and second yokes that are disposed about the central body over respective ones of the pairs of apertures, and a plurality of trunnions inserted through the yoke ears and into the apertures of the body to pivotally secure the yokes to the body. Each trunnion is non-rotatable relative to its respective yoke and a locking assembly inhibits movement of each opposite pair of trunnions away from each other thereby inhibiting movement of the opposite ears of each respective yoke away from each other.